The pair also have powers in the comics, with Tommy taking after his uncle Quicksilver with his superspeed and Billy having powers similar to his mother's reality-warping abilities which are the same powers they seem to have in the series on a much smaller scale. While Billy is still young and the extent of his powers in the MCU has yet to be seen, the comics provide a pretty good idea of how they could develop and the scope of what he will eventually be able to do.
Clairvoyance
One of the most useful aspects of Billy's powerset is that using intense concentration, Billy can determine a person's location and determine what their current state is over extreme distances. However, this ability is much harder to use if the person he's trying to find is someone he doesn't really know or have a strong connection with.
In the comics, he was able to mentally find the Scarlet Witch while using the focus of his brother and Magneto, despite her being believed to be dead. This is one of the few abilities he shows in WandaVision which uses to locate his father, Vision after he traveled outside of the Hex as well as know that his mother was going to attack the citizens of Westview before she actually did.
Telekinesis
Another ability Billy has is the power to move objects and people using only his mind. His telekinesis allows him to lift large objects with ease and even use them as projectiles against opponents like when he throws a car at a Skrull during a battle.
In the series, he uses this power to stop Tommy from running while he was using his superspeed in episode 5 and later in the finale to stop a bullet that was fired in his direction in mid-air before it could reach him.
Transmutation
Billy also has the power to change the form and function of something into something else completely different on a molecular level. He most frequently uses it to change his and his Young Avengers teammates' uniforms to look like normal clothes, allowing them to blend in, switching them back when necessary.
While he usually does this with clothing, he can even do it with other things, including people, like when he was able to make himself look like the Scarlet Witch to avoid being attacked by Doombots while trying to rescue his mother from Doctor Doom's castle.
Telepathy And Mental Manipulation
Billy has a wide range of psychic abilities that allow him to control his mind and the minds of others to an incredible degree. Billy also has telepathy, meaning that he can read the minds of others or communicate with them only using his and their thoughts.
He is powerful enough to fully experience the memories of others and can even erase memories as he does to Daniel DuBois aka the Executioner when he revealed that he had discovered that the secret identity of Hawkeye was Kate Bishop. Since his mind is his strongest weapon, Billy can use it to carry out psychic attacks, such as when he put into the Sons of the Serpent hate group into a coma with just a single thought.
Creation And Erasure
Not only can Wiccan change the appearance and purpose of things that already exist but he can create objects completely out of thin air. After moving into the Avengers facility with his boyfriend, Teddy AKA Hulkling, he created everything in his room to help them adjust to their new living situation.
He was able to fully furnish and decorate the room in a matter of seconds with just a single thought. Using those same reality-warping abilities, Billy is also able to completely remove something from existence. He uses this to destroy the parasite known as Mother from existence and temporarily destroy the army of parents that were infected by her in Young Avengers Vol. 2 #5.
Teleportation
Another ability Billy has is the power to teleport, not only himself, but others as well, over great distances. While his teleportation usually requires a spoken spell, it can still be done without one. He can summon other characters to bring them from wherever they previously were to his current location like when he forcibly brought Loki to face the Young Avengers or when he summoned Teddy's mom from another universe altogether.
He can also banish people away from him in order to protect himself or the other of his team like when he teleported Hawkeye away to safety. While the full range of this power is unknown, he can open portals to other planets and dimensions.
Healing
Luckily for his teammates, using one of his many spells, Billy can also cure people of their injuries. He heals his mother after she was injured by one of Hawkeye's incendiary arrows that was fired at her by Eli Bradley aka Patriot by repeating "I want her to heal" over and over in Avengers: The Children's Crusade #7.
Due to the difficulty of the spell, Billy needs total concentration for it to work which is why he was he was unable to save Hulkling's mother after she was blasted by fire from the Super-Skrull known as Kl'rt and killed in Young Avengers #9 due to the stress affecting his focus. So even though he can heal people from severe wounds, he can't bring them back from the dead.
Flight
Like most Marvel characters, Billy is capable of self-propelled flight which makes it easy for him to get around. When flying, he is able to easily carry Hulkling around while doing. He will often create a platform of energy for all the of the team to stand on so that he can move them from place to place as well.
However, the one thing that does set him apart from other heroes is the fact that he can also grant other characters the ability to fly on their own as he did for Captain America when they were working together in Avengers: The Children's Crusade #1. He can also do it unconsciously while using his other abilities, like when he started levitating while locating Patriot in Young Avengers #9.
Energy Manipulation
In of offensive powers, Billy can control and manipulate energy, which he normally uses to emit blasts in various forms including beams, waves, and bolts, which is especially useful in combat.
A single blast can knock out multiple opponents. Wiccan can also use the energy to create different types of constructs including disks, orbs, shields, and even forcefields which he used to be able to go up against Doctor Doom.
Elemental Manipulation
In addition to energy, Billy has also shown an ability to control various elements including ice, light, water, and fire. However, the element he manipulates the most is electricity which allows him to control electric fields, electric charges, and electric currents. It also allows him to generate lightning which was one of the first abilities he demonstrated when his powers began manifesting.
This power doesn't need a spell to use but can be used in combination with them and was strong enough to knock out the of the Wrecking Crew. He was even able to create a gigantic lightning bolt powerful enough to take out the Avengers including Captain Marvel and Iron Man in Avengers: The Children's Crusade #2, showing just how powerful he is.
